Strange green bars appear on Filled Maps

Did you use /bossbar?

@SlicedBlock

Look above.

Unable to reproduce.

@SlicedBlock

How?????...

Gah there R so many unique Minecraft things had happened on my computer :|.

Try following the instructions in the moderator's note in description section here.

In the future, please be more vigilant when using early development versions.

And please, for the love of the universe, stop using so many abbreviations - it is frustrating to read reports from you.